Problem: On the way to school, Karen became fixated on the puzzle game on her phone!

<image>

The game is played as follows. In each level, you have a grid with n rows and m columns. Each cell originally contains the number 0.

One move consists of choosing one row or column, and adding 1 to all of the cells in that row or column.

To win the level, after all the moves, the number in the cell at the i-th row and j-th column should be equal to gi, j.

Karen is stuck on one level, and wants to know a way to beat this level using the minimum number of moves. Please, help her with this task!

Input

The first line of input contains two integers, n and m (1 ≤ n, m ≤ 100), the number of rows and the number of columns in the grid, respectively.

The next n lines each contain m integers. In particular, the j-th integer in the i-th of these rows contains gi, j (0 ≤ gi, j ≤ 500).

Output

If there is an error and it is actually not possible to beat the level, output a single integer -1.

Otherwise, on the first line, output a single integer k, the minimum number of moves necessary to beat the level.

The next k lines should each contain one of the following, describing the moves in the order they must be done:

  * row x, (1 ≤ x ≤ n) describing a move of the form "choose the x-th row". 
  * col x, (1 ≤ x ≤ m) describing a move of the form "choose the x-th column". 



If there are multiple optimal solutions, output any one of them.

Examples

Input

3 5
2 2 2 3 2
0 0 0 1 0
1 1 1 2 1


Output

4
row 1
row 1
col 4
row 3


Input

3 3
0 0 0
0 1 0
0 0 0


Output

-1


Input

3 3
1 1 1
1 1 1
1 1 1


Output

3
row 1
row 2
row 3

Note

In the first test case, Karen has a grid with 3 rows and 5 columns. She can perform the following 4 moves to beat the level:

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In the second test case, Karen has a grid with 3 rows and 3 columns. It is clear that it is impossible to beat the level; performing any move will create three 1s on the grid, but it is required to only have one 1 in the center.

In the third test case, Karen has a grid with 3 rows and 3 columns. She can perform the following 3 moves to beat the level:

<image>

Note that this is not the only solution; another solution, among others, is col 1, col 2, col 3.

Solution (in PYTHON3):

Solution:
import sys

n, m = map(int, sys.stdin.readline().split())
l = []
row = [0]*n
col = [0]*m
flag = True
if m > n:
    for i in range(n):
        l.append(list(map(int, sys.stdin.readline().split())))
        tmp = min(l[i])
        row[i] = tmp

        if tmp!= 0:
            l[i] = list(map(lambda x:x-tmp, l[i]))

    l2 = list(map(list,zip(*l)))
    for i in range(m):
        tmp = min(l2[i])
        col[i] = tmp

        if tmp != 0:
            l2[i] = list(map(lambda x:x-tmp, l2[i]))
            # print(l2[i])
        if sum(l2[i]) != 0:
            print(-1)
            flag = False
            break
    if flag:
        print(sum(row)+sum(col))
        for i in range(n):
            for k in range(row[i]):
                print('row',i+1)
        for i in range(m):
            for k in range(col[i]):
                print('col', i+1)
else:
    for i in range(n):
        l.append(list(map(int, sys.stdin.readline().split())))

    l2 = list(map(list, zip(*l)))
    for i in range(m):
        tmp = min(l2[i])
        col[i] = tmp

        if tmp != 0:
            l2[i] = list(map(lambda x:x-tmp, l2[i]))

    l = list(map(list, zip(*l2)))
    for i in range(n):
        tmp = min(l[i])
        row[i] = tmp

        if tmp != 0:
            l[i] = list(map(lambda x:x-tmp, l[i]))

        if sum(l[i]) != 0:
            print(-1)
            flag = False
            break

    if flag:
        print(sum(row)+sum(col))
        for i in range(n):
            for k in range(row[i]):
                print('row',i+1)
        for i in range(m):
            for k in range(col[i]):
                print('col', i+1)